What causes white fingernails?

There are many reasons for white spots on fingernails. 1. Intestinal parasite infection. It can be diagnosed by stool routine plus floating egg test. 2. Local trauma. Generally, there is a history of trauma and local redness and pain. 3. Lack of vitamins and trace elements. It can be diagnosed by trace element examination, and targeted supplements when necessary. 4. Malnutrition or anemia. Generally accompanied by sallow complexion, dry and dull hair, etc., can be further examined for blood routine. 5. Fungal infection. Generally accompanied by nail deformation thickening.